To start the Mail Merge in the new Word 2007, click on the Mailings tab. The Ribbon, the groups of commands you see on each tab, replaces the toolbars and menus. Commands are organized in groups related to activities such as you see below in the Create, Start Mail Merge, and Write & Insert Fields groups on the Mailings tab.
Notice that the Address Block and Greeting Line fields are already inserted into this template letter. If you weren’t using a preformatted mail merge letter, you would just simply click on the links on the right to insert the Address block, Greeting line, or more items (more merge fields). You also have these same options on the Mailings toolbar at the top—you don’t have to use the wizard each time you do a mail merge. Pick the date and replace the letter content with your own and then go on to the next step to preview your letters by clicking on the link at the bottom of the task pane.